Earth Stove - help!

I just got my hands on an Earth Stove 1000C. Which seems to have been made in the early 80s. It's a grand old beautiful beast. But I can find nearly nothing at all about it online. Just a few forum posts and other people looking for manuals too. And a few videos of similar models.

It looks like it has very few hours of use on it.

I'd love to know specifications about what output it should produce or how you should use the several knobs on it. Including how the pipework to the catalytic converter works. It's more complicated than my existing stove.

And in this picture, I can't figure out what the smaller knob on the right is. Similar Earth Stove models say it's for temperature control but it doesn't regulate the combustible air intake. And in other models, it swings open and close a tiny box in the back... where this stove has a air duct going over it (to force air over the hot surface and out the front).

My intentions are to get some heat in the garage. So it doesn't have to be perfect. It could even leak smoke a little (but I doubt it will). But right now I feel like I'm guessing.

Considering the lack of quantity of responses on the wood burning stove sites, I thought maybe I'd find someone here who has this model or is better at googling manuals than I am. (I've been searching for 3-4 days on my own.)

Any help is appreciated.